Nan Wu , Yakup Niyazi, Michael Steventon, Harya Dwi Nugraha 

The Gippsland Basin is located in the southeastern continental margin of Australia and hosts a variety of important marine resources. Recent high-resolution seabed mapping reveals that seabed morphology is extremely complex in different regions of the Gippsland Basin (i.e. northern, central and southern regions), ranging from scarps, cyclic step trains, channels, canyons, gullies, and giant submarine landslides. Although previous studies have separately revealed the dominant sedimentary processes in different regions of the Gippsland Basin, these studies have not yet been able to explain the controlling factors behind this morphological complexity at a basin scale. We combine high-resolution multibeam bathymetric and seismic reflection datasets to investigate the reasons behind the significant changes in seabed morphology at the scale of the Gippsland Basin. We reveal that in the northern region of the Gippsland Basin, slope failures are the predominant sedimentary process, and giant submarine landslides are therefore the major deposits in the northern region. Additionally, we revealed that the submarine landslides are primed by the deposition and accumulation of contourites generated by the East Australian Current. In the central and southern regions, turbidity currents and canyoning processes are the major sedimentary process. We indicate that the seasonal Bass Cascade Current can carry large amounts of sediment, scour the seabed of the shelf and slope, and form turbidity currents, canyons, and a series of other erosional seabed morphologies. We suggest that slope gradient variation, different oceanography, and varied sedimentary evolution processes have jointly contributed to seabed morphological complexity in different regions of the Gippsland Basin. The high-resolution seabed morphological analysis within this study provides critical geomorphological and geological information for future submarine constructions (i.e. locating potential wind farms and telecommunication cable installations) along with geohazard prediction and mitigation (i.e. knowing the location of past and predicting future giant landslides).